In addition to liquid fuels, gaseous fuels are also increasingly used as fuels in internal combustion engines in the more recent past. In comparison with gasoline-operated internal combustion engines, gas-operated internal combustion engines, using natural gas or autogas, for example, are an attractive alternative for realizing savings potentials and reducing a CO2 emission. In addition, potentials with regard to reduced emissions are also obtainable. In an effort to achieve better efficiency, more attempts are also made to realize a direct injection of gas, where the gaseous fuel is injected directly into a combustion chamber of an internal combustion engine. An issue with gaseous fuels, especially natural gas, in comparison with gasoline or other liquid fuels is an exhaust-gas treatment. In particular if the gaseous fuel has methane (CH4) as the main component, an exhaust-gas treatment becomes more complex than in the case or longer-chained hydrocarbons of liquid fuels. This is due especially to a lower conversion rate of current catalytic converters in conjunction with required higher process temperatures. A sufficient exhaust-gas treatment cannot be ensured in the case of cold catalytic converters, in particular. Raising a temperature of the catalytic converter to the required process temperature as quickly as possible would therefore be important.